Implications of the Plastid Genome Sequence of Typha (Typhaceae, Poales) for Understanding Genome Evolution in Poaceae

Plastid genomes of the grasses (Poaceae) are unusual in their organization and rates of sequence evolution. There has been a recent surge in the availability of grass plastid genome sequences, but a comprehensive comparative analysis of genome evolution has not been performed that includes any related families in the Poales. We report on the plastid genome of Typha latifolia, the first non-grass Poales sequenced to date, and we present comparisons of genome organization and sequence evolution within Poales. Our results confirm that grass plastid genomes exhibit acceleration in both genomic rearrangements and nucleotide substitutions. Poaceae have multiple structural rearrangements, including three inversions, three genes losses (accD, ycf1, ycf2), intron losses in two genes (clpP, rpoC1), and expansion of the inverted repeat (IR) into both large and small single-copy regions. These rearrangements are restricted to the Poaceae, and IR expansion into the small single-copy region correlates with the phylogeny of the family. Comparisons of 73 protein-coding genes for 47 angiosperms including nine Poaceae genera confirm that the branch leading to Poaceae has significantly accelerated rates of change relative to other monocots and angiosperms. Furthermore, rates of sequence evolution within grasses are lower, indicating a deceleration during diversification of the family. Overall there is a strong correlation between accelerated rates of genomic rearrangements and nucleotide substitutions in Poaceae, a phenomenon that has been noted recently throughout angiosperms. The cause of the correlation is unknown, but faulty DNA repair has been suggested in other systems including bacterial and animal mitochondrial genomes

Propolis: bioactive molecules with antibacterial activity

<p>Propolis is a natural substance produced by honey bees from the exudates of certain trees and plants. Ιts composition varies according to the botanical and geographical origin, the seasonal timing of collection, and extraction methods. In this investigation we performed several tests regarding the solvent, the extraction method and the bioactivity. For this purpose, propolis extracts in 95 or 70% ethanol and standard bacterial strains were used (Staphylococcus aureus ATCC 29213, Micrococcus luteus ATCC 934 and Escherichia coli ATCC 25922). Bioactivity tests were performed by Disk Diffusion Assay and Well Diffusion Assay. Applying these methods of analysis, the growth inhibition zone for S. aureus και M. luteus was 2±0,3 cm και 1,8±0,2 cm, respectively. No inhibition was observed for the bacterial strain E. coli. These results indicate that the examined propolis sample has antibacterial activity against the tested Gram-positive bacteria.</p&gt

Investigation of the Phaseolus vulgaris circadian clock and the repressive role of the PvTOC1 factor by a newly established in vitro system

The circadian clock is crucial for the synchronization of an organism's physiology and metabolism with the geophysical time. In plants, previous work on the common bean (Phaseolus vulgaris) has identified various differing aspects of clock function compared to the widely studied Arabidopsis thaliana clock. However, transformation of legumes for the study of the circadian clock regulatory mechanisms is extremely laborious. In the present work, we describe an easy-to-follow and rapid method of preparing bean leaf protoplasts with high transformation potential and a functional circadian clock. In this system, we show that application of trichostatin A differentially changes the expression levels of several clock genes. More importantly, we investigate the effect of the clock protein PvTOC1 (Phaseolus vulgaris TIMING OF CAB EXPRESSION 1) on the activity of bean circadian promoters. We present new evidence on the function of PvTOC1 as a repressor of the promoter activity of its own gene, mediated by its conserved CCT (CONSTANS, CO-LIKE and TOC1) domain. Using our protoplast system we were able to uncover functions of the bean circadian clock and to identify an additional target of the PvTOC1clock transcription factor, not previously reported. © 2018 Elsevier Gmb